Artificial turf wtih improved tuft-lock

ABSTRACT

Embodiments of the present disclosure are directed to stretched filaments comprising a non-functionalized polyolefin and at least one functionalized polymer. The functionalized polymer is a propylene-based plastomer or elastomer having one or more functional groups grafted on the propylene-based plastomer or elastomer. The one or more functional groups is selected from the group consisting of amine groups and imide groups. The at least one functionalized polymer has a DSC melting point from 100° C. to 130° C. When the stretched filament is stretched to a stretch ratio of 5, the stretched filament has a tenacity greater than 0.90 cN/dtex

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to European Patent Application No.16382313.1, filed Jun. 30, 2016, which is incorporated by referenceherein in its entirety.

FIELD

Embodiments of the present disclosure generally relate to stretchedfilaments, articles incorporating stretched filaments, and theirmanufacture.

BACKGROUND

Synthetic or artificial turfs are increasingly being used as analternative to natural grass turf for use on sport athletic fields,playgrounds, landscaping, and in other leisure applications. To producean artificial turf, turf yarns may be extruded, and then tufted througha primary backing. A secondary backing may be applied to “glue” the turfyarn to the primary backing.

During the lifetime of the artificial turf, the yarn and backing aresubjected to continuous stresses. The durability of the artificial turfdepends in large part on the adhesion between the yarn and the backing.For example, if the adhesion between the yarn and the backing are poor,the yarn filaments are pulled off the backing as a result of thestresses, which may leave areas of the artificial turf without yarn.

Accordingly, alternative artificial turf yarns and/or artificial turfshaving improved adhesion between the yarn and the backing are desired.

SUMMARY

Disclosed in embodiments herein are stretched filaments. The stretchedfilaments comprise a blend of at least one functionalized polymer and anon-functionalized polyolefin. The functionalized polymer is apropylene-based plastomer or elastomer having one or more functionalgroups grafted thereon and having a Differential Scanning calorimetry(DSC) melting point from 100° C. to 130° C. The one or more functionalgroups are selected from the group consisting of amine groups and imidegroups. When the stretched filament is stretched to a stretch ratio of5, the stretched filament has a tenacity greater than 0.90 cN/dtex.Various embodiments described herein exhibit improved adhesion betweenthe stretched filament and the polyurethane backing, as will bedescribed in greater detail hereinbelow. Without being bound by theory,it is believed that the functionalized polymer enhances the polarity,thus increasing the adhesion of the filament to the polyurethanebacking.

Even further disclosed in embodiments herein are artificial turfs. Theartificial turfs comprise a primary backing, a secondary backing, and atleast one stretched filament. The stretched filaments comprise a blendof at least one functionalized polymer and a non-functionalizedpolyolefin. The functionalized polymer is a propylene-based plastomer orelastomer having one or more functional groups grafted thereon andhaving a DSC melting point from 100° C. to 130° C. The one or morefunctional groups are selected from the group consisting of amine groupsand imide groups. When the stretched filament is stretched to a stretchratio of 5, the stretched filament has a tenacity greater than 0.90cN/dtex.

Additional features and advantages of the embodiments will be set forthin the detailed description which follows, and in part will be readilyapparent to those skilled in the art from that description or recognizedby practicing the embodiments described herein, including the detaileddescription which follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing and the followingdescription describe various embodiments and are intended to provide anoverview or framework for understanding the nature and character of theclaimed subject matter. The accompanying drawings are included toprovide a further understanding of the various embodiments, and areincorporated into and constitute a part of this specification. Thedrawings illustrate the various embodiments described herein, andtogether with the description serve to explain the principles andoperations of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A pictorially depicts an exemplary monofilament extrusion linethat may be used to produce the stretched filaments according to one ormore embodiments shown and described herein;

FIG. 1B pictorially depicts an exemplary Collins fiber spinning linethat may be used to produce the stretched filaments according to one ormore embodiments shown and described herein; and

FIG. 2 pictorially depicts a cutaway view of an artificial turfaccording to one or more embodiments shown and described herein.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of stretchedfilaments and artificial turfs incorporating stretched filaments,characteristics of which are illustrated in the accompanying drawings.As used herein, “filament” refers to monofilaments, multifilaments,extruded films, fibers, yarns, such as, for example, tape yarns,fibrillated tape yarn, slit-film yarn, continuous ribbon, and/or otherfibrous materials used to form synthetic grass blades or strands of anartificial turf field.

Stretched Filaments

The stretched filaments described herein are formed from a blendcomprising at least one functionalized polymer and a non-functionalizedpolyolefin. The term “blend” means an intimate physical mixture (thatis, without reaction) of two or more polymers. A blend may or may not bemiscible (not phase separated at molecular level). A blend may or maynot be phase separated. A blend may or may not contain one or moredomain configurations, as determined from transmission electronspectroscopy, light scattering, x-ray scattering, and other methodsknown in the art. The blend may be effected by physically mixing the twoor more polymers on the macro level (for example, melt blending resinsor compounding) or the micro level (for example, simultaneous formingwithin the same reactor). As used herein, the term “non-functionalizedpolyolefin” refers to a polyolefin that is free of grafted moieties.Specifically, a “non-functionalized” ethylene based polymer in this caseis a resin only having ethylene and one other comonomer (e.g.,propylene, octene, hexene, butene, etc.) and a polymer that does not gothrough a second step of functionalization with another component. Invarious embodiments, the functionalized polymer is a propylene-basedplastomer or elastomer having one or more functional groups graftedthereon. The functional groups may be, for example, an amine group or animide group. The functionalized polymer has a DSC melting point from100° C. to 130° C. When the stretched filament is stretched to a stretchratio of 5, the stretched filament has a tenacity of greater than 0.9cN/dtex.

Non Functionalized Polyolefin

The non-functionalized polyolefin may include, by way of example and notlimitation, non-functionalized polyethylene or non-functionalizedpolypropylene. The term “polyethylene” refers to a polymer that containsmore than 50 weight percent polymerized ethylene monomer (based on thetotal amount of polymerizable monomers) and, optionally, may contain atleast one comonomer. The comonomer content may be measured using anysuitable technique, such as techniques based on nuclear magneticresonance (“NMR”) spectroscopy, and, for example, by ¹³C NMR analysis asdescribed in U.S. Pat. No. 7,498,282, which is incorporated herein byreference.

Suitable polyethylenes may include ethylene homopolymers, copolymers ofethylene and at least one comonomer, and blends thereof. As used herein,the term “copolymer” includes polymers made up of two or more differentmonomers, including trimers, tetramers, and the like. In variousembodiments, the polyethylene comprises greater than or equal to 70 wt.% of the units derived from ethylene and less than or equal to 30 wt. %of the units derived from one or more alpha-olefin comonomers. In someembodiments, the polyethylene comprises (a) greater than or equal to70%, greater than or equal to 75%, greater than or equal to 80%, greaterthan or equal to 85%, greater than or equal to 90%, greater than orequal to 92%, greater than or equal to 95%, greater than or equal to97%, greater than or equal to 98%, greater than or equal to 99%, greaterthan or equal to 99.5%, from 70% to 99.5%, from 70% to 99%, from 70% to97% from 70% to 94%, from 80% to 99.5%, from 80% to 99%, from 80% to97%, from 80% to 94%, from 80% to 90%, from 85% to 99.5%, from 85% to99%, from 85% to 97%, from 88% to 99.9%, 88% to 99.7%, from 88% to99.5%, from 88% to 99%, from 88% to 98%, from 88% to 97%, from 88% to95%, from 88% to 94%, from 90% to 99.9%, from 90% to 99.5% from 90% to99%, from 90% to 97%, from 90% to 95%, from 93% to 99.9%, from 93% to99.5% from 93% to 99%, or from 93% to 97%, by weight, of the unitsderived from the ethylene monomer; and (b) optionally, less than orequal to 30%, for example, less than 25%, or less than 20%, less than18%, less than 15%, less than 12%, less than 10%, less than 8%, lessthan 5%, less than 4%, less than 3%, less than 2%, less than 1%, from0.1 to 20%, from 0.1 to 15%, 0.1 to 12%, 0.1 to 10%, 0.1 to 8%, 0.1 to5%, 0.1 to 3%, 0.1 to 2%, 0.5 to 12%, 0.5 to 10%, 0.5 to 8%, 0.5 to 5%,0.5 to 3%, 0.5 to 2.5%, 1 to 10%, 1 to 8%, 1 to 5%, 1 to 3%, 2 to 10%, 2to 8%, 2 to 5%, 3.5 to 12%, 3.5 to 10%, 3.5 to 8%, 3.5% to 7%, or 4 to12%, 4 to 10%, 4 to 8%, or 4 to 7%, by weight, of units derived from oneor more alpha-olefin comonomers.

Suitable comonomers may include alpha-olefin comonomers, typicallyhaving no more than 20 carbon atoms. The one or more alpha-olefins maybe selected from the group consisting of C₃-C₂₀ acetylenicallyunsaturated monomers and C₄-C₁₈ diolefins. Those skilled in the art willunderstand that the selected monomers are desirably those that do notdestroy conventional Ziegler-Natta catalysts. For example, thealpha-olefin comonomers may have 3 to 10 carbon atoms, or 3 to 8 carbonatoms. Exemplary alpha-olefin comonomers include, but are not limitedto, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene,1-nonene, 1-decene, and 4-methyl-1-pentene. The one or more alpha-olefincomonomers may, for example, be selected from the group consisting ofpropylene, 1-butene, 1-hexene, and 1-octene; or in the alternative, fromthe group consisting of 1-butene, 1-hexene and 1-octene. In someembodiments, the polyethylene comprises greater than 0 wt. % and lessthan 30 wt. % of units derived from one or more of octene, hexene, orbutene comonomers.

The polyethylene may be made according to any suitable polymerizationprocess, including but not limited to solution, slurry, or gas phasepolymerization processes in the presence of a metallocene, constrainedgeometry catalyst systems, Ziegler-Natta catalysts, or bisphenyl phenolcatalyst systems. The solution, slurry, or gas phase polymerization mayoccur in a single reactor, or alternatively, in a dual reactor systemwherein the same product is produced in each of the dual reactors.Information on preparation and use of the multi-metallic catalysts arefound in U.S. Pat. No. 9,255,160, the disclosure of which isincorporated herein by reference in its entirety.

In embodiments herein, the polyethylene may be further characterized byone or more of the following properties: melt index (I₂), melt flowratio (I₁₀/I₂), or density, as previously described herein. Withoutbeing bound by theory, polyethylenes characterized by melt index (I₂),melt flow ratio (I₁₀/I₂), or density may be particularly well suited forblending with other filament components and/or extruding. For example,polymers with a melt index outside of a particular range may presentdifficulties in obtaining a homogeneous blend for extrusion.

Suitable polymers may include, for example, high density polyethylene(HDPE), linear low density polyethylene (LLDPE), ultra-low densitypolyethylene (ULDPE), homogeneously branched linear ethylene polymers,and homogeneously branched substantially linear ethylene polymers (thatis, homogeneously branched long chain branched ethylene polymers). Insome embodiments, the polyethylene is an LLDPE. The LLDPE may include,in polymerized form, a majority weight percent of ethylene based on thetotal weight of the LLDPE. In an embodiment, the LLDPE is a copolymer ofethylene and at least one ethylenically unsaturated comonomer. In oneembodiment, the comonomer is a C₃-C₂₀ α-olefin. In another embodiment,the comonomer is a C₃-C₈ α-olefin. In another embodiment, the C₃-C₈α-olefin is selected from propylene, 1-butene, 1-hexene, or 1-octene. Inan embodiment, the LLDPE is selected from the following copolymers:ethylene/propylene copolymer, ethylene/butene copolymer, ethylene/hexenecopolymer, and ethylene/octene copolymer. In a further embodiment, theLLDPE is an ethylene/octene copolymer. Commercial examples of suitableethylene-based copolymers include those sold under the trade namesATTANE™, AFFINITY™, DOWLEX™, ELITE™, ELITE AT™, and INNATE™ allavailable from The Dow Chemical Company (Midland, Mich.); LUMICENE®available from Total SA; and EXCEED™ and EXACT™ available from ExxonChemical Company.

In embodiments herein, the polyethylene may have a density of 0.900 g/ccto 0.950 g/cc. All individual values and subranges of at least 0.900g/cc to 0.950 g/cc are included and disclosed herein. For example, insome embodiments, the polyethylene has a density of 0.900 to 0.945 g/cc,0.900 to 0.940 g/cc, 0.900 to 0.935 g/cc, 0.910 g/cc to 0.945 g/cc,0.910 to 0.940 g/cc, 0.910 to 0.935 g/cc, 0.910 to 0.930 g/cc, 0.915 to0.940 g/cc, 0.915 to 0.923 g/cc, or 0.920 g/cc to 0.935 g/cc. Densitymay be measured in accordance with ASTM D792.

In embodiments herein, the polyethylene may have a melt index, I₂,measured in accordance with ASTM D1238 at 190° C. and 2.16 kg of 0.1g/10 min to 10 g/10 min. All individual values and subranges of at least0.1 g/10 min to 10 g/10 min are included and disclosed herein. Forexample, in some embodiments, the polyethylene may have a melt index,I₂, of 0.1 g/10 min to 9.5 g/10 min, 0.1 g/10 min to 9.0 g/10 min, 0.1g/10 min to 5 g/10 min, 0.5 g/10 min to 6 g/10 min, 1 g/10 min to 5 g/10min, 1.5 g/10 min to 4.5 g/10 min, or 2 g/10 min to 4 g/10 min. In otherembodiments, the polyethylene may have a melt index, I₂, of 0.7 g/10 minto 9.5 g/10 min, 0.7 g/10 min to 8 g/10 min, or 0.7 g/10 min to 5 g/10min. Melt index, I₂, may be measured in accordance with ASTM D1238 (190°C. and 2.16 kg).

In embodiments herein, the polyethylene may have a melt flow ratio,I₁₀/I₂, of less than 14. All individual values and subranges of lessthan 14 are included and disclosed herein. For example, in someembodiments, the polyethylene may have a melt flow ratio, I₁₀/I₂, ofless than 13.5, 13, 12.5, 10, or even 7.5. In other embodiments, thepolyethylene may have a melt flow ratio, I₁₀/I₂, of from 1.0 to 14, 2 to14, 4 to 14, 5 to 14, 5.5 to 14, 6 to 14, 5 to 13.5, 5 to 13, 5 to 12.5,5 to 12, 5 to 11.5, 5 to 11, 5.5 to 13.5, 5.5 to 13, 5.5 to 12.5, 5.5 to12, 5.5 to 11.5, 5.5 to 11, 6 to 13.5, 6 to 13, 6 to 12.5, 6 to 12, 6 to11.5, or 6 to 11. Melt index, I₁₀, may be measured in accordance withASTM D1238 (190° C. and 10.0 kg).

In other embodiments, the non-functionalized polyolefin includespolypropylene. The term “polypropylene” refers to a polymer thatcontains more than 50 weight percent polymerized propylene monomer(based on the total amount of polymerizable monomers) and, optionally,may contain at least one comonomer. Suitable polypropylenes may includepropylene homopolymers, copolymers of propylene and at least onecomonomer, and blends thereof. In embodiments herein, the polypropylenemay be a propylene homopolymer, a propylene copolymer, or a combinationthereof. The polypropylene homopolymer may be isotactic, atactic, orsyndiotactic. In some embodiments, the polypropylene is an isotacticpolypropylene homopolymer. In other embodiments, the polypropylene is apropylene/alpha-olefin copolymer. The propylene/alpha-olefin copolymermay be random or block, or an impact polypropylene copolymer. Impactpolypropylene copolymers may also include heterophasic polypropylenecopolymers, where polypropylene is the continuous phase and anelastomeric phase is uniformly dispersed therein.

In various embodiments, the polypropylene comprises greater than 50 wt.% of the units derived from propylene and less than 30 wt. % of theunits derived from one or more C₂ or C₄₋₂₀ alpha-olefin comonomers. Insome embodiments, the polypropylene comprises (a) greater than or equalto 55%, for example, greater than or equal to 60%, greater than or equalto 65%, greater than or equal to 70%, greater than or equal to 75%,greater than or equal to 80%, greater than or equal to 85%, greater thanor equal to 90%, greater than or equal to 92%, greater than or equal to95%, greater than or equal to 97%, greater than or equal to 98%, greaterthan or equal to 99%, greater than or equal to 99.5%, from greater than50% to 99%, from greater than 50% to 97%, from greater than 50% to 94%,from greater than 50% to 90%, from 70% to 99.5%, from 70% to 99%, from70% to 97% from 70% to 94%, from 80% to 99.5%, from 80% to 99%, from 80%to 97%, from 80% to 94%, from 80% to 90%, from 85% to 99.5%, from 85% to99%, from 85% to 97%, from 88% to 99.9%, 88% to 99.7%, from 88% to99.5%, from 88% to 99%, from 88% to 98%, from 88% to 97%, from 88% to95%, from 88% to 94%, from 90% to 99.9%, from 90% to 99.5% from 90% to99%, from 90% to 97%, from 90% to 95%, from 93% to 99.9%, from 93% to99.5% from 93% to 99%, or from 93% to 97%, by weight, of the unitsderived from propylene; and (b) optionally, less than 30 percent, forexample, less than 25 percent, or less than 20 percent, less than 18%,less than 15%, less than 12%, less than 10%, less than 8%, less than 5%,less than 4%, less than 3%, less than 2%, less than 1%, from 0.1 to 20%,from 0.1 to 15%, 0.1 to 12%, 0.1 to 10%, 0.1 to 8%, 0.1 to 5%, 0.1 to3%, 0.1 to 2%, 0.5 to 12%, 0.5 to 10%, 0.5 to 8%, 0.5 to 5%, 0.5 to 3%,0.5 to 2.5%, 1 to 10%, 1 to 8%, 1 to 5%, 1 to 3%, 2 to 10%, 2 to 8%, 2to 5%, 3.5 to 12%, 3.5 to 10%, 3.5 to 8%, 3.5% to 7%, or 4 to 12%, 4 to10%, 4 to 8%, or 4 to 7%, by weight, of units derived from one or moreC₂ or C₄₋₂₀ alpha-olefin comonomers.

Suitable comonomers may include C₂ or C₄₋₂₀ alpha-olefin comonomers. Theone or more alpha-olefin comonomers may have 2 carbon atoms or 4 to 20carbon atoms, C₂ or C₄₋₁₈, C₂ or C₄₋₁₀, or C₂ or 4 to 8 carbon atoms.Exemplary alpha-olefin comonomers include, but are not limited to,ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene,1-decene, and 4-methyl-1-pentene. The one or more alpha-olefincomonomers may, for example, be selected from the group consisting ofethylene, 1-butene, 1-hexene, and 1-octene. In some embodiments, thepolypropylene comprises greater than 0 wt. % and less than 30 wt. % ofunits derived from one or more of octene, hexene, butene, or ethylenecomonomers.

The polypropylene can be made using any method for polymerizingpropylene and, optionally, one comonomer. For example, gas phase, bulkor slurry phase, solution polymerization or any combination thereof canbe used. Polymerization can be a one stage or a two or multistagepolymerization process, carried out in at least one polymerizationreactor. For two or multistage processes different combinations can beused, e.g. gas-gas phase, slurry-slurry phase, slurry-gas phaseprocesses. Suitable catalysts can include Ziegler-Natta catalysts, asingle-site catalyst (metallocene or constrained geometry), ornon-metallocene, metal-centered, heteroaryl ligand catalysts, orcombinations thereof. Exemplary polypropylene polymers may includemetallocene polypropylenes, such as, ACHIEVE™ 3584, available from theExxonMobil Chemical Company, and LUMICENE™ MR 2001, available from TotalResearch & Technology Feluy; and Ziegler-Natta polypropylenes, such as,HG475FB, available from Borealis AG, MOPLEN™ HP2814, available fromLyondell Basell Industries Holdings, B.V., Sabic 518A, available fromSaudi Basic Industries Corporation.

In embodiments herein, the polypropylene may be further characterized byone or more of the following properties: melt flow rate (MFR₂), meltflow ratio (MFR₁₀/MFR₂), or density, as described herein.

In embodiments herein, the propylene based polymer may have a density offrom about 0.890 g/cc to about 0.910 g/cc. All individual values andsubranges of at least 0.890 g/cc to 0.910 g/cc are included anddisclosed herein. For example, in some embodiments, the polyethylene hasa density of 0.890 to 0.905 g/cc, 0.890 to 0.900 g/cc, 0.890 to 0.895g/cc, 0.895 g/cc to 0.910 g/cc, 0.900 to 0.910 g/cc, or 0.905 to 0.910g/cc. Density may be measured in accordance with ASTM D792.

In embodiments herein, the polypropylene may have a melt flow rate,MFR₂, of 0.5 g/10 min to 25 g/10 min when measured according to ASTMD1238 at 230° C. and 2.16 kg. All individual values and subranges of atleast 0.5 g/10 min to 25 g/10 min are included and disclosed herein. Forexample, in some embodiments, the polypropylene may have a melt flowrate, MFR₂, of 0.5 g/10 min to 22.5 g/10 min, 0.5 g/10 min to 20 g/10min, 0.5 g/10 min to 15 g/10 min, 0.5 g/10 min to 10 g/10 min, 1 g/10min to 10 g/10 min, 1.5 g/10 min to 10 g/10 min, or 3 g/10 min to 10g/10 min. In one embodiment, the polypropylene may have a melt flowrate, MFR₂, of 2.0 g/10 min to 4.0 g/10 min when measured at 230° C. and2.16 kg. Melt flow rate, MFR₂, may be measured in accordance with ASTM D1238 (230° C. and 2.16 kg).

In embodiments herein, the polypropylene may have a melt flow ratio,MFR₁₀/MFR₂, of less than 10. All individual values and subranges of lessthan 10 are included and disclosed herein. For example, in someembodiments, the polypropylene may have a melt flow ratio, MFR₁₀/MFR₂,of less than 10, 9, or even 7. In other embodiments, the polypropylenemay have a melt flow ratio, MFR₁₀/MFR₂, of from 1.0 to 10, 2 to 9, or 3to 7. Melt flow rate, MFR₁₀, may be measured in accordance with ASTM D1238 (230° C. and 10.0 kg).

Functionalized Polymer

As stated above, the stretched filaments described herein furtherinclude at least one functionalized polymer. In various embodiments, thefunctionalized polymer has a propylene-based plastomer or elastomer asits base polymer, and is herein referred to as a propylene-basedplastomer or elastomer, and has one or more functional groups graftedthereon. In one embodiment, the at least one functionalized polymer is apolymer formed from a propylene-based plastomer or elastomer having atleast one organic compound selected from an “amine-containing compound”or an “imide-containing compound” grafted thereon. As used herein, theterm “amine-containing compound” refers to a chemical compoundcomprising at least one amine group. As used herein, the term“imide-containing compound” refers to a chemical compound comprising atleast one imide group.

In embodiments described herein, the propylene-based plastomer orelastomer is a propylene/ethylene copolymer or a propylene/C₄-C₂₀alpha-olefin copolymer. In one embodiment, the propylene-based plastomeror elastomer is a propylene/ethylene copolymer. In another embodiment,the propylene-based plastomer or elastomer is a propylene/C₄-C₂₀alpha-olefin copolymer, or a C₄-C₁₀ alpha-olefin, or a C₄-C₈alpha-olefin. In another embodiment, the alpha-olefin is selected fromthe group consisting of ethylene, 1-butene, 1-hexene, and 1-octene. Thepropylene-based plastomer or elastomer comprises at least 60 wt. % ofthe units derived from propylene and between 1 and 40 wt. % of the unitsderived from ethylene (based on the total amount of polymerizablemonomers). All individual values and subranges of at least 60 wt. % ofthe units derived from propylene and between 1 and 40 wt. % of the unitsderived from ethylene are included and disclosed herein. For example,the propylene-based plastomer or elastomer based polymer can includegreater than or equal to 60%, greater than or equal to 65%, greater thanor equal to 70%, greater than or equal to 75%, greater than or equal to80%, greater than or equal to 85%, greater than or equal to 90%, greaterthan or equal to 92%, greater than or equal to 95%, greater than orequal to 97%, greater than or equal to 98%, greater than or equal to99%, greater than or equal to 99.5%, from greater than 60% to 99%, fromgreater than 60% to 97%, from greater than 60% to 94%, from greater than60% to 90%, from 70% to 99.5%, from 70% to 99%, from 70% to 97% from 70%to 94%, from 80% to 99.5%, from 80% to 99%, from 80% to 97%, from 80% to94%, from 80% to 90%, from 85% to 99.5%, from 85% to 99%, from 85% to97%, from 88% to 99.9%, 88% to 99.7%, from 88% to 99.5%, from 88% to99%, from 88% to 98%, from 88% to 97%, from 88% to 95%, from 88% to 94%,from 90% to 99%, from 90% to 99% from 90% to 99%, from 90% to 97%, from90% to 95%, from 93% to 99%, from 93% to 99% from 93% to 99%, or from93% to 97%, by weight, of the units derived from propylene; and (b)optionally, less than 40 percent, for example, less than 40%, less than35%, less than 30%, less than 25%, or less than 20%, less than 18%, lessthan 15%, less than 12%, less than 10%, less than 8%, less than 5%, lessthan 4%, less than 3%, less than 2%, from 1 to 20%, from 1 to 15%, 1 to12%, 1 to 10%, 1 to 8%, 1 to 5%, 1 to 3%, 1 to 2%, 2 to 10%, 2 to 8%, 2to 5%, 3.5 to 12%, 3.5 to 10%, 3.5 to 8%, 3.5% to 7%, or 4 to 12%, 4 to10%, 4 to 8%, or 4 to 7%, by weight, of units derived from ethylene.

The functionalized propylene-based elastomer or plastomer has a densityfrom 0.850 g/cc to 0.930 g/cc. In another embodiment, thepropylene/alpha-olefin copolymer has a density from 0.870 g/cc to 0.930g/cc. In another embodiment, the propylene/alpha-olefin copolymer has amelt flow rate, MFR₂, measured at 230° C. and 2.16 kg, from 1 g/10 minto 20 g/10 min.

In another embodiment, the functionalized propylene-based elastomer orplastomer is a propylene/ethylene copolymer. In a further embodiment,the propylene/ethylene copolymer has a density from 0.850 g/cc to 0.930g/cc, or from 0.870 g/cc to 0.930 g/cc. In another embodiment, thepropylene/ethylene copolymer has a melt flow rate (MFR₂), measured inaccordance with ASTM D1238 at 230° C. and 2.16 kg, from 1 g/10 min to 20g/10 min. In embodiments herein, the propylene/ethylene copolymer has anethylene content of less than about 5 wt. %. In another embodiment, thepropylene/ethylene copolymer has an ethylene content of less than about4 wt. %. For example, the propylene/ethylene copolymer may have anethylene content of greater than about 0 wt. % to about 5 wt. %,including all individual values and subranges from greater than about 0wt. % to about 5 wt. %. In embodiments, the propylene/ethylenecompolymer has an ethylene content of from 0.001 wt. % to 5 wt. %, from0.01 wt. % to 5 wt. %, from 0.1 wt. % to 5 wt. %, from 0.001 wt. % to 4wt. %, from 0.01 wt. % to 4 wt. %, from 0.1 wt. % to 4 wt. %, from 0.1wt. % to 3.5 wt. %, from 0.1 wt. % to 3 wt. %, from 0.1 wt. % to 2.5 wt.%, or the like, Various methodologies may be used to determine ethylenecontent, including but not limited to, mass balance calculations andFTIR.

In various embodiments, the at least one functionalized propylene-basedplastomer or elastomer has a differential scanning calorimetry (DSC)melting point from about 100° C. to about 130° C. or from about 110° C.to about 120° C. The functionalized propylene-based plastomer orelastomer of various embodiments has a percent crystallinity of lessthan or equal to 30%, or less than or equal to 25%, or less than orequal to 22.5%, as measured by DSC. In some embodiments, thefunctionalized propylene-based plastomer or elastomer has a percentcrystallinity of from about 10% to about 30%, as measured by DSC,including all individual values and subranges from 10% to 30%. Suitablepropylene-based plastomer or elastomers that may be functionalized mayinclude, by way of example and not limitation, VERSIFY™ 3000,commercially available from The Dow Chemical Company (Midland, Mich.).

Methods of Making Functionalized Polymers

In various embodiments, the at least one functionalized polymer isformed by grafting an “amine-reactive” group onto a propylene-basedplastomer or elastomer to form a grafted propylene-based plastomer orelastomer and then reacting the grafted propylene-based plastomer orelastomer with an “amine-containing compound” or “imide-containingcompound.”

For example, in an embodiment, the at least one functionalized polymeris formed from a process comprising the following steps: 1) graftingonto the backbone of a propylene-based plastomer or elastomer at leastone compound comprising at least one “amine-reactive” group to form agrafted propylene-based plastomer or elastomer; 2) reacting aprimary-secondary diamine with the grafted propylene-based plastomer orelastomer; and 3) wherein step 2) takes place subsequent to step 1),without the isolation of the grafted propylene-based plastomer orelastomer (i.e., removal of the grafted propylene-based plastomer orelastomer from the solution containing the compound containing theamine-reactive group and the propylene-based plastomer or elastomer),and wherein both steps take place in a melt reaction. The term“amine-reactive group,” as used, refers to a chemical group or chemicalmoiety that can react with an amine group. Amine-reactive groupsinclude, but are not limited to, maleic anhydride, acrylic acid,methacrylic acid, glycidyl acrylate, glycidyl methacrylate.

As used herein, the term “primary-secondary diamine” refers to a diaminemade up of a primary amine and a secondary amine. Suitableprimary-secondary diamines include compounds of structure (I):

H₂N—R₁—NH—R₂  (I).

In structure (I), R₁ is a divalent hydrocarbon radical, and preferably alinear hydrocarbon of the formula —(CH₂)_(n)—, where n is greater than,or equal to, 2, n is from 2 to 10, from 2 to 8, or even from 2 to 6. R₂is a monovalent hydrocarbon radical containing at least 2 carbon atoms,and optionally may be substituted with a heteroatom containing group,such as OH or SH. In embodiments, R₂ a linear hydrocarbon of the formula—(CH₂)_(n)CH₃, where n is from 1 to 10, from 1 to 9, from 1 to 7, oreven from 1 to 5. In embodiments, the primary-secondary diamine isselected from the group consisting N-ethylethylenediamine,N-phenylethylenediamine, N-phenyl-1,2-phenylene-diamine,N-phenyl-1,4-phenylenediamine, and N-(2-hydroxyethyl)-ethylenediamine.

In another embodiment, the at least one functionalized propylene-basedplastomer or elastomer comprises the following functional groupcovalently bonded to the propylene-based plastomer or elastomerbackbone:

wherein “NR₁NHR₂” may be derived from a primary-secondary diamineselected from the group of compounds of structure (I) below:

H₂N—R₁—NH—R₂  (I),

wherein R₁ is a divalent hydrocarbon radical selected from the groupconsisting of alkylene or phenylene, such as, by way of example and notlimitation, —CH₂CH₂—, -para-phenylene-, or ortho-phenylene-, and R₂ is amonovalent hydrocarbon radical containing at least 2 carbon atoms, andoptionally may be substituted with a heteroatom containing group, suchas an alkyl or aryl group. In embodiments, the alkyl or aryl group is anethyl or a phenyl group.

In another embodiment, the at least one functionalized polymer is formedfrom a process comprising the following steps: 1) functionalizing thepropylene-based plastomer or elastomer with at least one compoundcomprising at least one “amine-reactive” group to form a graftedpropylene-based plastomer or elastomer; 2) blending the graftedpropylene-based plastomer or elastomer, in a solid, non-molten form,with at least one primary-secondary diamine; 3) imbibing theprimary-secondary diamine into the grafted propylene-based plastomer orelastomer; 4) reacting the primary-secondary diamine with the graftedpropylene-based plastomer or elastomer to form an imide functionalizedpropylene-based plastomer or elastomer. The term “imbibing,” and similarterms, as used, refers to the process in which a compound is absorbedinto a polymer solid, particle, pellet, or article. More particularly, apolyolefin is first functionalized with a group reactive with aminefunctionality, such as an anhydride group. At least one diamine is mixedwith the functionalized polyolefin at a temperature below the meltingpoint of the polyolefin. In some embodiments, the temperature is roomtemperature, although other temperatures are contemplated. The diamineis allowed to absorb or imbibe into the polyolefin, and reacts withdiamine reactive group to form a succinamic acid. The reaction of thediamine with the diamine reactive functional group to form the imidering can then be completed by subjecting the mixture to a thermaltreatment, such as in a melt extrusion process. The imbibing processhelps to ensure that the diamine is thoroughly mixed with the polyolefinfor an efficient functionalization reaction.

In another embodiment, the at least one functionalized polymer is formedfrom a process comprising the following steps: 1) grafting onto thebackbone of a propylene-based plastomer or elastomer at least onecompound comprising at least one “amine-reactive” group to form agrafted propylene-based plastomer or elastomer; 2) reacting aalkanolamine with the grafted propylene-based plastomer or elastomer;and wherein step 2) takes place subsequent to step 1), without theisolation of the grafted propylene-based plastomer or elastomer, andwherein both steps 1) and 2) take place in a melt reaction.

In further embodiments, the alkanolamine is selected from the groupconsisting of 2-aminoethanol, 2-amino-1-propanol, 3-amino-1-propanol,2-amino-1-butanol, 2-(2-aminoethoxy)-ethanol and 2-aminobenzyl alcohol.

Without being bound by theory, increased grafting on the polypropyleneincreases the melt flow rate, I₂, measured at 230° C. and 2.16 kg, ofthe polymer. Accordingly, in order to maintain a viscosity that iscompatible with the viscosity of the non-functionalized polyolefin, invarious embodiments, the propylene-based plastomer or elastomer has agraft level of from about 0.1 wt. % to about 3.0 wt. %, depending on theparticular polypropylene-based elastomer or plastomer employed. Thegraft level may be determined by Fourier Transform Infrared Spectroscopy(FTIR). Without being bound by theory, compatibility of the melt indicesof the propylene-based plastomer or elastomer and the non-functionalizedpolyolefin enables the components of the stretched filaments to besuitably blended for extrusion.

In various embodiments, the stretched filaments include from about 1 wt.% to about 30 wt. % of the functionalized polymer, including allindividual values and subranges from 1 wt. % to 30 wt. %. Suchindividual values and subranges are disclosed herein. In anotherembodiment, the stretched filaments include from about 1 wt. % to about20 wt. % of the functionalized polymer. In yet another embodiment, thestretched filaments include from about 5 wt. % to about 20 wt. % of thefunctionalized polymer. In embodiments described herein, the stretchedfilaments include from about 68 wt. % to about 99 wt. % of thenon-functionalized polyolefin, including all individual values andsubranges from 68 wt. % to 99 wt. %. In other embodiments, the stretchedfilaments include from about 75 wt. % to about 99 wt. % of thenon-functionalized polyolefin, from about 80 wt. % to about 99 wt. % ofthe non-functionalized polyolefin, or even from about 85 wt. % to about99 wt. % of the non-functionalized polyolefin.

In embodiments herein, the stretched filaments may further include oneor more additives. Nonlimiting examples of suitable additives includeantioxidants, pigments, colorants, UV stabilizers, UV absorbers, curingagents, cross linking co-agents, boosters and retardants, processingaids, fillers, coupling agents, ultraviolet absorbers or stabilizers,antistatic agents, nucleating agents, slip agents, plasticizers,lubricants, viscosity control agents, tackifiers, anti-blocking agents,surfactants, extender oils, acid scavengers, and metal deactivators. Inan embodiment, colorant, such as SICOLEN™ green 85-125345 (availablefrom BASF), may be added in an amount of less than about 10 wt. %, lessthan about 8 wt. %, less than about 6 wt. %, or even less than about 4wt. %. In another embodiment, a processing aid, such as ARX-741(available from Argus), may be added in an amount of less than about 2wt. %, less than about 1.5 wt. %, or even less than about 1 wt. %.Additives can be used in amounts ranging from about 0.001 wt. % to morethan about 10 wt. % based on the weight of the composition.

In various embodiments, when the stretched filament is stretched to astretch ratio of 5, the stretched filament has a tenacity greater than0.90 cN/dtex or from about 0.9 cN/dtex to about 1.5 cN/dtex. Thefilament is stretched after the filament has been formed using anextrusion process, but may be stretched using an inline process where astretching unit is connected with an extrusion unit used to make thefilament that forms the stretched filament. However, the filament mayalso be stretched in a process unconnected with the extrusion process.Tenacity is defined as the tensile force at break divided by the linearweight (dtex). The linear weight (in dtex) of a monofilament is equal tothe weight of weighing 50 meters of the monofilament. In embodiments,the stretched filament may exhibit an elongation of at least 55% or atleast 60%. In embodiments, the stretched filament may exhibit anelongation of from about 30% to about 150%, from about 90% to about110%, or from about 95% to about 105%. Elongation, which is the strainat break, is measured according to ISO 188/ASTM E145 on a Zwick tensiletester on a filament length of 250 mm and extension rate of 250mm/minute until the filament breaks. In embodiments, the tenacity andelongation values may impact the durability of the filaments and, thus,the artificial turf made therefrom.

In some embodiments herein, the stretched filaments may exhibit ashrinkage of less than 20%. Because the stretched filaments exhibit lowshrinkage, shorter filaments may be used to maintain the final desiredyarn length of the stretched. All individual values and subranges ofless than 20% are included and disclosed herein. For example, in someembodiments, the stretched filaments may exhibit a shrinkage lower than19%, lower than 18%, lower than 15% or lower than 14%. The shrinkage maybe determined by submerging 1 meter of yarn in a heated oil bath at 90°C. for 20 seconds.

Process for Making Stretched Filaments

The stretched filaments described herein may be made using anyappropriate process for the production of stretched filament frompolymer compositions as the stretched filaments described herein areprocess independent. In some embodiments, a method of manufacturing astretched filament comprises providing a blend of a non-functionalizedpolyolefin and a functionalized propylene-based plastomer or elastomeras previously described herein, and extruding the blend of thenon-functionalized polyolefin and the functionalized propylene-basedplastomer or elastomer into a stretched filament. The stretched filamentmay be extruded to a specified width, thickness, and/or cross-sectionalshape depending on the physical dimensions of the extruder. As mentionedabove, the stretched filament can include a monofilament, amultifilament, a film, a fiber, a yarn, such as, for example, tape yarn,fibrillated tape yarn, or slit-film yarn, a continuous ribbon, and/orother fibrous materials used to form synthetic grass blades or strandsof an artificial turf field.

Referring to FIGS. 1A and 1B, the following describes one such exemplaryprocess 100 that may be used to make stretched filaments. In process100, stretched filaments are made by extrusion. For example, thenon-functionalized polyolefin and the functionalized propylene-basedplastomer or elastomer may be blended together along with any additivesto form an extrusion mixture. Suitable stretched filament extruders maybe equipped with a single polyethylene/polypropylene general purposescrew and a melt pump (“gear pump” or “melt pump”) to precisely controlthe consistency of polymer volume flow into the die 105, as shown inFIGS. 1A and 1B. Stretched filament dies 105 may have multiple singleholes for the individual filaments distributed over a circular orrectangular spinplate. The shape of the holes corresponds to the desiredfilament cross-section profile, including for example, rectangular,dog-bone, and v-shaped. A standard spinplate has 50 to 160 die holes ofspecific dimensions. Lines can have output rates from 150 kg/h to 350kg/h.

The stretched filaments 110 may be extruded into a water bath 115 with adie-to-water bath distance of from 16 to 40 mm. Coated guiding bars inthe water redirect the filaments 110 towards the first takeoff set ofrollers 120. The linear speed of this first takeoff set of rollers 120may vary from 15 to 70 m/min. The first takeoff set of rollers 120 canbe heated and used to preheat the filaments 110 after the waterbath 115and before entering the stretching oven 125. The stretching oven 125 maybe a heated air or water bath oven. The filaments 110 may be stretchedin the stretching oven 125 to a predetermined stretched ratio. In someequipment configurations, the stretching oven 125 is replaced by one ormore heated godets 300-310, as shown in FIG. 1B. In some embodiments,the stretch ratio is at least 4. In other embodiments, the stretch ratiois at least 4.5, 4.8, 5.0, 5.2, or 5.5. The stretching ratio is theratio between the speed of the second takeoff set of rollers 130 afterthe stretching oven and the speed of the first takeoff set of rollers120 before the stretching oven (V2/V1 as shown in FIG. 1A). The secondtakeoff set of rollers 120 may be run at a different (higher or lower)speed than the first set of rollers 130. In embodiments in whichstretching is performed over heated godets, the stretching ratio is theratio between the speed of the godet 310 and the speed of the godet 300.

After the filaments 110 are passed over the second takeoff set ofrollers 130, they are then drawn through a set of three annealing ovens135, 140, and 145. The three annealing ovens 135, 140, and 145 may beeither a hot air oven with co- or countercurrent hot air flow, which canbe operated from 50° C. to 150° C. or a hot water-oven, wherein thefilaments 110 are oriented at temperatures from 50° C. to 98° C. At theexit of the first annealing oven 135, the filaments 110 are passed ontoa third set of rollers 150 that may be run at a different (higher orlower) speed than the second set of rollers 130. The linear velocityratio of the third set of rollers 150 located after the oven to thesecond set of rollers 130 located in front of the oven may be referredto as either a stretching or relaxation ratio. At the exit of the secondannealing oven 140, the filaments 110 are passed onto a fourth set ofrollers 155 that may be run at a different (higher or lower) speed thanthe third set of rollers 150. At the exit of the third annealing oven145, the filaments 110 are passed onto a fifth set of rollers 160 thatmay be run at a different (higher or lower) speed than the fourth set ofrollers 155. In some embodiments, the annealing ovens 135, 140, and 145may be replaced with heated godets 320 and 330, as depicted in FIG. 1B.

The stretched filament may optionally undergo further post-extrusionprocessing (e.g., annealing, cutting, etc.).

Artificial Turf

One or more embodiments of the stretched filaments described herein maybe used to form an artificial turf field. Referring to FIG. 2, depictedis a cutaway view of an artificial turf field 200 according to one ormore embodiments shown and/or described herein. The artificial turffield 200 comprises a primary backing 205 having a top side 210 and abottom side 215; and at least one stretched filament 220 as previouslydescribed herein. The at least one stretched filament 220 is affixed tothe primary backing 205 such that the at least one stretched filament220 provides a tufted face 225 extending outwardly from the top side 210of the primary backing 205. As used herein, “affix,” “affixed,” or“affixing” includes, but is not limited to, coupling, attaching,connecting, fastening, joining, linking or securing one object toanother object through a direct or indirect relationship. The tuftedface 225 extends from the top side 210 of the primary backing 205, andcan have a cut pile design, where the stretched filament loops may becut, either during tufting or after, to produce a pile of singlestretched filament ends instead of loops.

The primary backing 205 can include, but is not limited to, woven,knitted, or non-woven fibrous webs or fabrics made of one or morenatural or synthetic fibers or yarns, such as polypropylene,polyethylene, polyamides, polyesters, and rayon. The artificial turffield 200 may further comprise a secondary backing 230 bonded to atleast a portion of the bottom side 215 of the primary backing 205 suchthat the at least one stretched filament 220 is affixed in place to thebottom side 215 of the primary backing 205. The secondary backing 230may comprise polyurethane (including, for example, polyurethane suppliedunder the name ENFORCER™ or ENHANCER™ available from The Dow ChemicalCompany (Midland, Mich.)) or latex-based materials, such as,styrene-butadiene latex, or acrylates.

The primary backing 205 and/or secondary backing 230 may have aperturesthrough which moisture can pass. The apertures may be generally annularin configuration and are spread throughout the primary backing 205and/or secondary backing 230. Of course, it should be understood thatthere may be any number of apertures, and the size, shape and locationof the apertures may vary depending on the desired features of theartificial turf field 200.

The artificial turf field 200 may be manufactured by providing at leastone stretched filament 220 as described herein and affixing the at leastone stretched filament 220 to a primary backing 205 such that that atleast one stretched filament 220 provides a tufted face 225 extendingoutwardly from a top side 210 of the primary backing 205. The artificialturf field 200 may further be manufactured by bonding a secondarybacking 230 to at least a portion of the bottom side 215 of the primarybacking 205 such that the at least one stretched filament 220 is affixedin place to the bottom side 215 of the primary backing 205.

The artificial turf field 200 may optionally comprise a shock absorptionlayer underneath the secondary backing 230 of the artificial turf field.The shock absorption layer (not shown) can be made from polyurethane,PVC foam plastic or polyurethane foam plastic, a rubber, a closed-cellcrosslinked polyethylene foam, a polyurethane underpad having voids,elastomer foams of polyvinyl chloride, polyethylene, polyurethane, andpolypropylene. Non-limiting examples of a shock absorption layer areDOW® ENFORCER™ Sport Polyurethane Systems, and DOW® ENHANCER™ SportPolyurethane Systems, both available from The Dow Chemical Company(Midland, Mich.).

The artificial turf field 200 may optionally comprise an infillmaterial. Suitable infill materials include, but are not limited to,mixtures of granulated rubber particles like SBR (styrene butadienerubber) recycled from car tires, EPDM (ethylene-propylene-dienemonomer), other vulcanized rubbers or rubber recycled from belts,thermoplastic elastomers (TPEs) and thermoplastic vulcanizates (TPVs).

The artificial turf field 200 may optionally comprise a drainage system.The drainage system allows water to be removed from the artificial turffield and prevents the field from becoming saturated with water.Nonlimiting examples of drainage systems include stone-based drainagesystems, EXCELDRAIN™ Sheet 100, EXCELDRAIN™ Sheet 200, AND EXCELDRAIN™EX-T STRIP (available from American Wick Drain Corp., Monroe, N.C.).

The embodiments described herein may be further illustrated by thefollowing non-limiting examples.

Test Methods Density

Density is measured according to ASTM D792, and is reported in grams percubic centimeter (g/cm³ or g/cc).

Melt Index

Melt index, or I₂, is measured according to ASTM D1238 at 190° C. and2.16 kg, and is reported in grams eluted per 10 minutes. Melt index, orI₁₀, is measured in accordance with ASTM D1238 at 190° C. and 10 kg.

Melt Flow Rate

Melt flow rate, MFR₂, for propylene-based polymers is measured inaccordance with ASTM D1238 at 230° C. and 2.16 kg, and is reported ingrams eluted per 10 minutes. Melt flow rate, or MFR₁₀, forpropylene-based polymers is measured in accordance with ASTM D1238 at230° C. and 10 kg, and is reported in grams eluted per 10 minutes.

Differential Scanning Calorimetry (DSC)

Baseline calibration of the TA Instrument's DSC Q1000 is performed byusing the calibration wizard in the software. First, a baseline isobtained by heating the cell from −90° C. to 300° C. without any samplein the aluminum DSC pan. After that, sapphire standards are usedaccording to the instructions in the wizard. Then about 3-4 mg of afresh indium sample is analyzed by heating the sample to 100° C. toequilibrate and followed by heating the sample from 100° C. to 180° C.at a heating rate of 10° C./min. The heat of fusion and the onset ofmelting of the indium sample are determined and checked to be within1.3° C. from 156.6° C. for the onset of melting and within 0.8 J/g from28.71 J/g for the heat of fusion.

Samples of polymer are pressed into a thin film at a temperature of 160°C. About 5 to 8 mg of sample is weighed out and placed in a DSC pan. Alid is crimped on the pan to ensure a closed atmosphere. The sample panis placed in the DSC cell and then heated at a high rate of 10° C./minto 230° C. The sample is kept at this temperature for about 3 minutes.Then the sample is cooled at a rate of 10° C./min to −40° C., and keptisothermally at that temperature for 3 minutes. The sample is thenheated at a rate of 10° C./min until melting is complete or 230° C. Theresulting enthalpy curves from the second scan analyzed for DSC meltingpoint and heat of fusion. The DSC % crystallinity is calculated forpropylene-based polymers as follows:

${{DSC}\mspace{14mu} \% \mspace{14mu} {Crystallinity}} = {\frac{\Delta \; H_{f}^{obs}}{165\frac{J}{g}} \times 100\%}$

where ΔH_(f) ^(obs) is the observed heat of fusion taken from the“second melting curve.”

Fourier Transform Infrared Spectroscopy (FTIR)

The amount of grafting was determined by Fourier Transform InfraredSpectroscopy (FTIR). In particular, 2 g of the grafted polymer wasdissolved in 150 mL toluene. The mixture was heated and stirred untilall of the grafted polymer was in solution. The solution was cooled for10 minutes, and 100 mL of cold methane was added to form a precipitate.The solution was suctioned through #2 qualitative filter paper tocollect the precipitate. The precipitate was dried in a forced air ovenfor 1 hour at 100° C., then pressed into a film. The film was thenprocessed using an FTIR spectrometer.

Basis Weight

The basis weight of filaments is typically reported in the industry bythe dtex value. The dtex of a monofilament is equal to the weight ingrams of 10 km of the monofilament.

Tensile Strength

The tensile strength of filaments is measured on according to ISO 527.

Elongation

Elongation was measured according to ISO 527.

Shrinkage

The shrinkage of a monofilament (expressed as the percentage reductionin length of a 1 meter sample of the monofilament) is measured byimmersing the monofilament for 20 seconds in a bath of silicon oilmaintained at 90° C. Shrinkage is then calculated as: (lengthbefore−length after)/length before *100%.

Tenacity

Tenacity is determined using a Zwick tensile tester, operating on a 260mm length of the monofilament, and using an extension speed of 250mm/minute until the filament breaks. The tenacity (in cN/dtex) is thetensile stress (in cN) at break divided by the linear weight (in dtex).The linear weight (in dtex) of a monofilament is equal to the weight ofweighing 50 meters of the monofilament.

Adhesion

Samples were prepared by applying a polyurethane (PU) reaction mixtureto polyethylene terephthalate (PET) film at a thickness of 0.76 mm usinga wet-film applicator. One filament was carefully married to thecoating, making an effort to minimize the inclusion of air pockets. ThePET/PU/filament sample was placed between two plates of preheated safetyglass to maintain sample flatness, then placed in an 85° C. oven forfive (5) minutes to cure the PU. Samples were conditioned for seven (7)days to allow the PU to fully cure. For each filament composition, themeasurement was repeated six (6) times. The delamination of the filamentfrom the PU was initiated by hand and continued on an Instron tensiletester. The adhesion force was recorded.

Examples

The following conducted examples illustrate one or more of the featuresof the stretched filaments of the present disclosure. A functionalizedpolymer was prepared and used to prepare a blend including thefunctionalized polymer and a non-functionalized polyolefin. The blendwas also used to prepare stretched filaments. Testing was carried out onthe stretched filaments.

Functionalized Polymer Preparation

An imidized propylene-based elastomer or plastomer resin was produced bya two-step process. First, a propylene-based elastomer or plastomer wasgrafted with maleic anhydride (MAH). The MAH-grafted polymer was thenfurther reacted with a diamine. A schematic of the reaction usingN-ethylethylendiamine is shown below:

The grafting experiments were completed on a Coperion 25 mm twin-screwreactive extrusion line. The reactive extrusion line had 12 barrelsections and 9 temperature zones. Maleic anhydride was dissolved inmethyl ethyl ketone (MEK) solvent, at 50 wt. % maleic anhydride, basedon the weight of the solution. The maleic anhydride was added to the MEKin a flask and stirred overnight with a magnetic stirrer bar. The MEKsolvent, maleic anydride, and peroxide were injected in Barrel #4(temperature zone 3) of the extruder. The liquid pump system was an ISCOD1000 positive displacement pump, commercially available as Alltech HPLCpump, model 627.

VERSIFY™ 3000 propylene-ethylene copolymer, available from The DowChemical Company (Midland, Mich.), was added into the extruder using aK-Tron model KCLKT20 twin-screw, loss-in-weight feeder. The feed ratewas 15 lb/h at the fixed 200 rpm screw speed.

Once the MAH graft process was completed, the imidization step wasperformed using N-ethylethylenediamine (DEDA, CAS 110-72-5). Thereaction was run in excess of DEDA to minimize the risk of cross-linkingand push the conversion of the reaction to completion. Samples wereprepared using a 2.5:1 molar ratio of primary amine to MAH content.

The amount of grafting was determined by Fourier Transform InfraredSpectroscopy (FTIR), according to the method described above.

Table 1 provides selected properties of the functionalizedpropylene-based plastomer or elastomer.

TABLE 1 DSC Grafted Density MFR₂ Melting DSC level Polymer (g/cc) (g/10min) Point Crystallinity (wt %) Functionalized 0.898 7.2 116° C. 20.8%0.5 Propylene-Based Plastomer or Elastomer

Polymer Blend

A blend including a functionalized polymer and a non-functionalizedpolyolefin was prepared as outlined in Table 2. Various examples andcomparative examples (Examples 1 and 2 and Comparative Examples 1 and 2)included DOWLEX™ SC 2107G, available from The Dow Chemical Company(Midland, Mich.), as the non-functionalized polyolefin. DOWLEX™ SC 2107Gis a linear low density polyethylene (LLDPE) resin with a density of0.917 g/cc, as measured according to ASTM D792, melt index, I₂, of 2.3g/10 min, measured according to ASTM D1238 at 190° C., 2.16 kg, and amelt flow ratio, I₁₀/I₂, of from 6 to 14, measured according to ASTMD1238 (190° C. and 10 kg). A third example (Example 3) included BraskemD105.02, available from Braskem (Sao Paolo, Brazil), as thenon-functionalized polyolefin. Braskem D105.02 is a non-functionalizedpolypropylene homopolymer with a MFR₂ of 3 g/10 min measured accordingto ASTM D1238 at 230° C., 2.16 kg.

In particular, two examples (Examples 1 and 2) were prepared by mixingDOWLEX™ SC 2107G with 5% of the functionalized propylene-based plastomeror elastomer in Table 1 and 10% of the functionalized propylene-basedplastomer or elastomer in Table 1, respectively. A third example(Example 3) was prepared by mixing Braskem D105.02 with 10% of thefunctionalized propylene-based plastomer or elastomer in Table 1.

Two comparative examples were additionally prepared. One comparativeexample (Comparative Example 1) included only DOWLEX™ SC 2107G. Thesecond comparative example (Comparative Example 2) included DOWLEX™ SC2107G and 5% functionalized polyethylene in Table 1. Table 2 providesthe contents of the various examples in wt. %.

Stretched Filament

The stretched filaments were prepared from the examples. The filamentformulations are presented as wt. % of the total filament formulation inTable 2 below. The additives, color (color masterbatch BASF Sicolen85125345) and a processing aid (Argus ARX-741) were blended with thepolymer compositions prior to extrusion. Each of the filaments wasprepared on a Collins fiber spinning line (See FIG. 1B) as describedherein.

TABLE 2 Comp. Comp. Example 1 Example 2 Example 3 Ex. 1 Ex. 2 DOWLEX ™89.3 84.6 0 94 89.3 SC 2107G (non- functionalized polyethylene) Braskem0 0 84.6 0 0 D105.02 (non- functionalized polypropylene) Functionalized0 0 0 0 4.7 Polyethylene (functionalized ENGAGE ™) Functionalized 4.79.4 9.4 0 0 Propylene- based Elastomer or Plastomer (FunctionalizedVERSIFY ™ 3000) color 5.0 5.0 5.0 5.0 5.0 masterbatch BASF Sicolen85125345 Argus ARX- 1.0 1.0 1.0 1.0 1.0 741 Total 100 100 100 100 100

Table 3 provides specific conditions of the equipment used in preparingthe filaments.

TABLE 3 Parameter Value Die type Mexican Hat (total 4 holes) ExtruderTemperature melt T 220° C. Distance die-to-water bath 40 mm (see FIG. 1)Temperature first godet 97° C. Temperature second, third, and fourth112° C. godets Speed of fourth godet 140 m/min

The filaments shown in Table 4—Example 1, Example 2, Example 3, Comp.Ex. 1, and Comp. Ex. 2—were produced at stretch ratio of 5. In thiscase, the speed of the first godet was 28 m/min (speed of finalgodet/5). The filaments shown in Table 5—Example 1 and Comp. Ex. 2—wereproduced with stretch ratio of 3.66. In this case, the speed of thefirst godet was 38.25 m/min (speed of final godet/3.66). The stretchedfilaments were tested for shrinkage, tenacity, elongation, and adhesionto polyurethane, and the results are shown in Tables 4 and 5. Tenacityand elongation were measured on a Zwick tensile tester on a filamentlength of 250 mm and extension rate of 250 mm/min until the filamentbreaks. Tenacity is defined as the tensile force at break divided by thelinear weight (dtex). Elongation is the strain at break. Adhesion topolyurethane was measured by according to the method provided above. Theadhesion force was recorded and is reported in Tables 4 and 5.

TABLE 4 Filament Results at Stretch Ratio of 5 Comp. Comp. Example 1Example 2 Example 3 Ex. 1 Ex. 2 Shrinkage (%) 13.8 11.7 16 12.6 BrokeTenacity 1.12 1.23 2.05 1.00 during (cN/dtex) Elongation (%) 60.8 64.278.1 51.4 stretching Adhesion to 0.29 0.41 0.20 0.12 Polyurethane (PU)(N)

TABLE 5 Filament Results at Stretch Ratio of 3.66 Example 1 Comp. Ex. 2Shrinkage 8.0 10.5 (%) Tenacity 0.73 0.64 (cN/dtex) Elongation 83.8 73.7(%) Adhesion to 0.26 0.15 PU (N)

As shown in Table 4, tenacity, elongation, and adhesion to polyurethaneincreased with the addition of a functionalized polymer. Additionally,as shown in Tables 4 and 5, filaments including a functionalizedpropylene-based plastomer or elastomer showed improvement over filamentsincluding a functionalized polyethylene (Comp. Ex. 2), which brokeduring stretching.

Without being bound by theory, it is believed that duringfunctionalization of the propylene-based plastomer or elastomer, thepolymer chain is cut, making it easier for split chains to migrate tothe surface of the filament and improve adhesion to the polyurethane.However, it is believed that functionalization of polyethylene createslonger branches, thereby resulting in the opposite effect. It is furtherbelieved that the longer branches and crosslinking that occur uponfunctionalization of polyethylene adversely impact the orientation ofthe filament, preventing the filament from being stretched to a stretchratio of 5 and achieving the desired tenacity.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, if any, including any cross-referenced orrelated patent or application and any patent application or patent towhich this application claims priority or benefit thereof, is herebyincorporated herein by reference in its entirety unless expresslyexcluded or otherwise limited. The citation of any document is not anadmission that it is prior art with respect to any feature disclosed orclaimed herein or that it alone, or in any combination with any otherreference or references, teaches, suggests or discloses any suchinvention. Further, to the extent that any meaning or definition of aterm in this document conflicts with any meaning or definition of thesame term in a document incorporated by reference, the meaning ordefinition assigned to that term in this document shall govern.

While particular embodiments of the present disclosure have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the disclosure. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this disclosure.

1. A stretched filament formed from a blend comprising: at least onefunctionalized polymer, wherein the functionalized polymer is apropylene-based plastomer or elastomer having one or more functionalgroups grafted on the propylene-based plastomer or elastomer, whereinthe one or more functional groups is selected from the group consistingof amine groups and imide groups, wherein the at least onefunctionalized polymer has a differential scanning calorimetry (DSC)melting point of from 100° C. to 130° C.; and a non-functionalizedpolyolefin; wherein when the stretched filament is stretched to astretch ratio of 5, the stretched filament has a tenacity greater than0.90 cN/dtex.
 2. The stretched filament of claim 1, wherein thenon-functionalized polyolefin comprises a polyethylene having a density(measured according to ASTM D792) of from 0.900 g/cc to 0.950 g/cc and amelt index, I₂, measured according to ASTM D 1238 (190° C. and 2.16 kg),of from 0.1 g/10 min to 10 g/10 min.
 3. The stretched filament of claim1, wherein the non-functionalized polyolefin comprises a polyethylenehaving a density (measured according to ASTM D792) of from 0.915 g/cc to0.940 g/cc and a melt index, I₂, measured according to ASTM D 1238 (190°C. and 2.16 kg), of from 0.7 g/10 min to 5 g/10 min.
 4. The stretchedfilament of claim 2, wherein the polyethylene has a melt flow ratio,I₁₀/I₂, of from 5 to 14, wherein I₁₀ is measured according to ASTM D1238(190° C. and 10 kg).
 5. The stretched filament of claim 1, wherein thenon-functionalized polyolefin comprises a polypropylene homopolymer. 6.The stretched filament of claim 5, wherein the non-functionalizedpolyolefin has a melt flow rate (MFR₂) of 0.5 g/10 min to 25 g/10 min.7. The stretched filament of claim 5, wherein the polypropylenehomopolymer has a MFR₂ of 0.5 g/10 min to 10 g/10 min.
 8. The stretchedfilament of claim 1, wherein the functionalized polymer has a graftlevel of from 0.1 wt. % to 3.0 wt. %.
 9. The stretched filament of claim1, wherein the propylene-based plastomer or elastomer is apropylene/ethylene copolymer or a propylene/alpha-olefin copolymerwherein the alpha-olefin is a C₄-C₂₀ alpha-olefin.
 10. The stretchedfilament of claim 1, wherein the at least one functionalized polymer hasa melt flow rate (MFR₂) measured according to ASTM D 1238 (230° C. and2.16 kg), of from 1 g/10 min to 20 g/10 min.
 11. An artificial turfsystem comprising: a primary backing; a secondary backing; and thestretched filament of claim 1.